1. Field of the Invention
This invention relates to a control valve device for the control of a consumer, such as a dual-action consumer. The control valve device includes a control valve that controls the connection of an admission side of the consumer with a pump and a return side of the consumer with a reservoir. The control valve device also has a regeneration function, by means of which the return side of the consumer can be connected with the admission side of the consumer.
2. Technical Considerations
Control valve devices are used for the control of consumers in mobile machines, for example to control a stick cylinder of an excavator. To prevent cavitation on the admission side of the consumer and to achieve an increased speed of movement of the consumer (which requires a flow that exceeds the discharge flow delivered by the pump), conventional control valve devices are provided with a regeneration function. The regeneration function connects the return side of the consumer with the admission side. As a result of which, on the admission side of the consumer, the flow of pressure fluid flowing out of the return side of the consumer is available in addition to the discharge flow delivered by the pump.
A control valve device is described in DE 198 44 699 A1. The regeneration function is formed by regeneration lines, each of which connects a return line that leads from the control valve to the reservoir with the respective admission side of the consumer. Check valves that open to the admission side of the consumer are located in these regeneration lines. For the regeneration function, the return line is shut off by means of a valve device that is located in the return line downstream of the connections of the regeneration lines. When the regeneration function is active, the pressure fluid that is being discharged from the return side of the consumer flows via the control valve and the return line (which is shut off by means of the valve device) into the regeneration line which is in communication with the admission side of the consumer and thus to the admission side of the consumer. However, as a result of this routing of the flow of pressure fluid of the regeneration function via the control valve, long flow paths are required. This leads to high line losses and requires a great deal of construction effort and expense. The valve device is also necessary for the shutoff of the return line that leads from the control valve to the reservoir, which leads to a further increase in the construction effort and expense for the control valve device.
Therefore, it is an object of this invention to provide a control valve device of the general type described above but which has a regeneration function with low line losses and requires less construction effort and expense than known devices.